Improvement in iron-truss bridges



TJC. CLARKE.

Improvement in Iron Truss Bridges.

Patented Nov. 5,1872

AM PHOTO LITHDGRAFHIC cawxr'ossamvsls PRUCESSY) NITED STATES PATENTOEEIoE.

THOMAS C. CLARKE, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOB TO CLARKE,REEVES 8t 00., OF SAME PLACE.

IMPROVEMENT lNlRON-TRUSS BRIDGES.

Specification forming part of Letters Patent No. 13%,803, dated November5, 1872.

To all whom it may concern:

Be it known that I, THOMAS CURTIS CLARKE, of Philadelphia, Pennsylvania,have invented certain Improvementsin Truss-Frame Bridges, of which thefollowing is a specification:

My invention consists of a truss-frame brid g in which the floor-beams,posts, and braces are connected and supported as fully describedhereafter, the object of my invention being to insure economy andsimplicity in the construction of iron bridges.

In the accompanying drawing, Figure l is a side view of sufficient of atruss-frame bridge to illustrate my invention Fig. 2, a transversesection of Fig. 1 on the line 1 2; Fig. 3, a sectional plan on the line3 4, Fig. 2; Fig. 4, a perspective view, illustrating the mode ofconnecting the post to the floor-beam; Fig. 5, a perspective view of thebearer; and Fig. 6 illustrates a modification of my invention.

A represents the lower portion of the vertical post of a truss-framebridge; B and B, the diagonal and counter-diagonal stays; D D, the lowerchord-links E, the bearer, and F the pin which connects the diagonalsand chord-links tothe bearer, and G part of one of the floor-beams. Itis the common practice in bridges of this class to suspend thefloorbeams from the pin F by boltsa plan which has been considered bymany engineers to be more or less precarious, especially as the nuts ofthe bolts, on the integrity of which the safety of the structuredepends, are exposed,

and may be easily tampered with by evil-dis.

posed persons. I obviate this evil in the manner which I will nowproceed to describe: The post is, in the present instance, made ofwrought-iron, in accordance with the invention of S. J. Reeves, patentedJune 17, 1862, and is composed of four flanged bars, a a and b b,-asbest observed in the perspective view, Fig. 4, and at the lower end ofthe post the opposite bars a a are cut away for the admission of theends of the floor-beam G, which is of the well-known character known asa Phoe nix beam. The bars b b of the post are con tinued downward, andare arranged to bear on blocks 01 d fitted to the lower flange, and tothe web of the beam, a horizontal bolt, e, passing through the whole, asshown in Fig. 4. The flange of the beam and the blocks 01 drest on thebearer E, Fig. 5, which is maintained in position by a simplesteady-pin,f, this bearer being composed, in the present instance, oftwo plain plates, m m, of wrought-iron, riveted to the flanges of astrip, n, of channel-iron. The pin F passes through the said plates andthrough the eyes of the diagonals B and B, and through those of thelower chord-links D D. It will now be seen that the floor-beam as Y wellas the post is supported by the pin which connects together thediagonals and lower chord-links.

The simplicity of my invention and the economical results attained willbe readily under stood by those familiar with structures of this class.

It is not essential in carrying out my invention that the post should beof the precise character illustrated in the drawing; the post may, forinstance, be constructed as shown in Fig. 6, the web being removed atthe lower end of the posts, so that the latter fit over and embrace thefioonbeam; in fact, a post of any form may be used, providing it isprepared at the lower end for combination with the beam, substantiallyin the manner shown.

I claim as my invention- The combination, with the bearer E, pin F, anddiagonals and links, of the beam G and pivot A, the side bars of .whichrest on blocks d supported directly by the bearer, the whole beingconnected as set forth.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

THOMAS C. CLARKE.

Witnesses WM. A. STEEL, HARRY SMITH.

